Kamis, 29 September 2011
Senin, 26 September 2011
GULF OIL HAMMERS FISH
Deepwater Horizon oil coming ashore at Chandeleur Islands, LA. Credit: Jeffrey Warren, Grass Roots Mapping project, via Wikimedia Commons. |
Even minuscule amounts of BP's crude oil has affected fish in profound ways in the Gulf of Mexico�even when oil in the water was nondetectable. This according to a paper in early view in PNAS (Proceedings of the National Academy of Science).
The problems showed up as genetic responses in liver tissue and as aberrant protein expression in gill tissues�and they lived on in fish even after their environment looked and tested clean.
Gulf killifish, Fundulus grandis. Credit: USGS. |
Researchers from Louisiana State University, Texas State University, and Clemson University studied the 2010 Deepwater Horizon oil catastrophe on Gulf killifish (Fundulus grandis).
They collected water and tissue samples from six sites�though only one, Louisiana's Barataria Bay was heavily oiled. They collected at three times:
- Once in early May before oil had reached shore
- Once in late June when the marshes were fouled
- Once in late August when oil was no longer visible
(A) Location of ?eld sampling sites. (B) Photograph (by A.W.) of the GT ?eld site on 28 June 2010 showing oil and minnow traps in the marsh. (C ) Proximity of nearest surface oil to each ?eld site was determined by synthetic aperture radar, where rows are ?eld sites and columns are days. Light gray=no data; black=the nearest surface oil at a distance of >4 km; increasing intensity of red=closer proximity of oil. Three ?eld sampling trips are highlighted in blue boxes. Credit: Andrew Whitehead, et al. PNAS. DOI:10.1073/pnas.1109545108. |
The researchers found that exposure to BP's crude oil caused the same kind of changes in gene expression in adult killifish from the marshes as in killifish embryos exposed to contaminated water samples in the lab. These types of changes are known to:
- cause developmental abnormalities
- to diminish embryo survival
- to lower reproductive success
Gill tissues important for maintaining critical body functions were also damaged by altered protein expression correlated to oil exposure. Worse, these effects persisted long after the visible oil disappeared from the marshes. Exposures in the lab to developing embryos induced similar cellular responses.
"This is of concern, because early life-stages of many organisms are particularly sensitive to the toxic effects of oil, and because marsh contamination occurred during the spawning season of many important species," says lead author Andrew Whitehead.
The research echoes ongoing studies from the Exxon-Valdez catastrophe showing that sub-lethal biological effects of oil continue to impact herring and salmon populations long after the disaster. The new paper indicates Gulf killifish are suffering similar early sub-lethal effects in the Gulf.
And as with the Exxon Valdez, the fish are proving far more sensitive indicators of exposure and contamination than the environmental chemistry.
"Though the fish may be 'safe to eat' based on low chemical burdens in their tissues, that doesn�t mean that the fish are healthy or that the fish are capable of reproducing normally," says Andrew Whitehead
And as with the Exxon Valdez, the fish are proving far more sensitive indicators of exposure and contamination than the environmental chemistry.
"Though the fish may be 'safe to eat' based on low chemical burdens in their tissues, that doesn�t mean that the fish are healthy or that the fish are capable of reproducing normally," says Andrew Whitehead
The paper:
Whitehead, A., B. Dubansky, C. Bodinier, T. Garcia, S. Miles, C. Pilley, V. Raghunathan, J. Roach, N. Walker, R. Walter, C.D. Rice, and F. Galvez. Genomic and physiological footprint of the Deepwater Horizon oil spill on resident marsh fishes. Proceedings of the National Academy of Sciences. DOI:10.1073/pnas.1109545108.
HAECKEL'S OCEAN
Actiniae [sea anemones] |
Acsidiae [sea squirts] |
Cyrtoidea [archaic: radiolarians] |
Chaetopoda [archaic: segmented worms] |
Hexacoralla [corals & allies] |
Gamochonia [archaic: cephalopods] |
Decapoda [crustacean] |
Ostraciontes [boxfishes & allies] |
Diatomea [diatoms] |
Discomedusae [archaic: jellyfish] |
Cubomedusae [archaic: box jellyfish] |
Ernst Heinrich Philipp August Haeckel (16 February 1834-9 August 191) was an eminent German biologist, naturalist, philosopher, physician, professor, and artist who discovered, described and named thousands of new species, mapped a genealogical tree relating all life forms, and coined many terms in biology, including anthropogeny, ecology, phylum, phylogeny, stem cell, and the kingdom Protista. Haeckel promoted and popularized Charles Darwin's work in Germany and developed the controversial recapitulation theory ("ontogeny recapitulates phylogeny") claiming that an individual organism's biological development, or ontogeny, parallels and summarizes its species' evolutionary development, or phylogeny.
The published artwork of Haeckel includes over 100 detailed, multi-colour illustrations of animals and sea creatures (see: Kunstformen der Natur, "Art Forms of Nature"). As a philosopher, Ernst Haeckel wrote Die Weltr�tsel (1895�1899, in English, The Riddle of the Universe, 1901), the genesis for the term "world riddle" (Weltr�tsel); and Freedom in Science and Teaching to support teaching evolution.
In the United States, Mount Haeckel, a 13,418 ft/4,090 m summit in the Eastern Sierra Nevada, overlooking the Evolution Basin, is named in his honor, as is another Mount Haeckel, a 2,941 m/9,649 ft summit in New Zealand; and the asteroid 12323 Haeckel.
All plates from Ernst Haeckel's Kunstformen der Natur, courtesy of Wikimedia Commons.
Sabtu, 24 September 2011
CHOWDER WORTH SURFACING FOR
And here's the story of Ivar's chowder from a 2009 article in the Seattle Times:
He has been called the greatest self-promoter in the history of Seattle. And now, more than 24 years after he died at age 79, Ivar Haglund apparently has managed one more fantastic stunt. Underwater billboards that date to around 1954. Anchored to the bottom of Puget Sound with concrete footings. Yes, at the bottom of Puget Sound. At around 55 to 80 feet in depth, depending on the tide, and near the shore. You know, just in case you were in a personal submarine cruising along Elliott Bay, or Edmonds, or Alki Point. There they would be:
"Ivar's Chowder. Worth surfacing for. 75� a cup."
Or, "Diver's special. Kids 12 & Under Eat Free* with regular entr�e. Includes Jell-O."
There apparently were plans for seven underwater billboards. In the past month, the company has had divers bring up three of the billboards�about 7 by 22 feet and made of stainless steel�using a map found in their founder's immense collection of artifacts stored on the top floor of the chain's headquarters at Pier 54...
"This still could be a hoax. Someone could be doing something," says Bob Donegan, president of Ivar's. "That's why we're being careful on the authentication"...
Seattle historian Paul Dorpat also says he doesn't believe the billboards are hoaxes. If anyone should know about Ivar Haglund, it is Dorpat. He is writing a book about Haglund, and interviewed him a number of times. Dorpat also has been granted access to all of Haglund's archives. "As far as I can tell, it's the real thing," says Dorpat about the papers documenting Ivar's plans for the billboards. It was Dorpat who found the documents. Dorpat remembered a poem that Haglund likely wrote in the mid-1950s that celebrated cross-sound submarine passenger service, with lines that included:
"As we go ping-ping-pinging along, We sing our happy song, Up periscope down down down, We're diving in Puget Sound... "
Ivar, obviously, was a man with vast imagination.
Underwater Americana at its best.
UPDATE: Thanks to Sam for pointing out it was a hoax. Neverthess, primed by Ivar's, I ate chowder the night this was posted.
Jumat, 23 September 2011
WATER WINGS
Flying gurnard. Credit: cralize via Wikimedia Commons. / Spotted eagle ray. Credit: john norton via Wikimedia Commons. / Green sea turtle. Credit: Mila Zinkova via Wikimedia Commons. / Weedy sea dragon. Credit: Richard Ling (Rling) via Wikimedia Commons. / Lionfish. Credit: Jens Petersen via Wikimedia Commons. / Cuttlefish. Via. / Icefish. Credit: Uwe Kils via Wikimedia Commons. / Humpback whales. Via. / Hammerhead shark. Via. / Manatee. Via. / Sea lions. Credit: NOAA. / Manta ray. Via. / Flying fish. Via.
Kamis, 22 September 2011
AURORA AUSTRALIS FROM THE ISS
From the NASA Multimedia Video Gallery:
Video of the Aurora Australis taken by the crew of Expedition 29 on board the International Space Station. This sequence of shots was taken September 17, 2011 from 17:22:27 to 17:45:12 GMT, on an ascending pass from south of Madagascar to just north of Australia over the Indian Ocean.
Rabu, 21 September 2011
Selasa, 20 September 2011
SECRET SHARK NURSERIES
Catshark egg casings. Credit: OpenCage.info via Wikimedia Commons. |
The fascinating deep-water cold-seep worlds of mud volcanoes and methane seeps are powered by the process of chemosynthesis not photosynthesis�a difference that gets them branded as 'extreme' environments.
But it turns out that cold seeps are also fantastically rich nursery grounds for deep-water sharks�specifically for catsharks, Galeus melastomus�and for skates�possibly of the genus Bathyraja.
Glass skatefish, Bathyraja transpicia. Credit: Sergio Gabriel Nahk via Wikimedia Commons. |
The authors of a new paper in MEPS (Marine Ecology Progress Series) found living egg casings at two modern sites:
- the North Alex Mud Volcano in the eastern Mediterranean Sea, at water depths of about 500 meters/1,640feet
- the Concepci�n Methane Seep Area in the south-east Pacific Ocean, at depths of about 700 meters/2,300feet
Close-up photograph of the tubeworm Lamellibrachia luymesi from a cold seep at 550-meter/1,800-foot depth in the Gulf of Mexico. Credit: Charles Fisher via Wikimedia Commons. |
They also found evidence in the fossil record at the Bear River Cold-Seep Deposit in the North Pacific off Washington that cold deep-water ecosystems have been important to elasmobranchs for at least 35 million years:
[W]e collected 30 fossilized shark egg capsules and fragments thereof. All of the capsules were found closely associated with abundant remains of bathymodiolin mussels, hexactinellid sponges, and tubeworms... The most similar extant egg capsules to those found at the BRSD are those of the deep-water catshark Apristurus spp.
Spongehead catshark, Apristurus spongiceps. Credit: NOAA Ocean Explorer. |
As to why some sharks and skates lay their eggs in deep-water cold seeps�and have done so for so long�the authors suggest:
- that coral reeflike marine life in chemosynthetic ecosystems provide holdfasts for egg capsules�on tubeworms, gorgonians, and sponges, and between carbonate boulders
- that enhanced currents around the reefs provide ventilation important for the development of the egg capsules
What's not yet known is the role�if any�that seeps play in the ecology of the hatchling sharks and skates:
We do not know if the seep biostrome is still of importance for the neonate and juvenile sharks and skates after hatching because we could not confirm their presence in the vicinity of the egg capsules. Neonate catsharks and skates are reported to leave their nurseries, probably to escape predation, and to migrate into deeper or shallower depths until they return for mating. However, the seep biostrome could provide ample and localized food sources in the form of small fishes, crustaceans, mollusks, and annelids.
Black catshark, Galeus melastomus. Via. |
The authors conclude that 'extreme' seeps are hardly isolated from the 'non-extreme' waters around them:
By serving as nurseries for deep-water marine predators, cold seeps are important components of deep-sea ecosystems and should not be considered as only extreme and exceptional habitats; their presence or absence is likely to influence faunal diversity along continental margins.
The paper:
- ? Treude T, Kiel S, Linke P, Peckmann J, Goedert JL (2011) Elasmobranch egg capsules associated with modern and ancient cold seeps: a nursery for marine deep-water predators. Mar Ecol Prog Ser 437:175-181. DOI:10.3354/meps09305
? Open access.
Senin, 19 September 2011
SNEAK PREVIEW: WHALE SHARKS GET NOSEY
A whale shark tilts upright and yanks on a net, trying to make off with a fisherman's catch. Credit: �Michael Aw/National Geographic. |
An amazing National Geographic photo essay in the October issue�due on newsstands 27 September�tells of the novel relationship between whale sharks and fishermen off Papua, Indonesia.
Vying for position under a feeding platform, male whale sharks�two of about twenty that visit this spot�scramble for a snack. Credit: �Michael Aw/National Geographic. |
Normally these 50,000-pound/22,680-kilogram behemoths are tough to find. They cross ocean basins and can dive more than a mile/1.6 kilometers deep. Some travel to Australia's Ningaloo Reef for the annual coral spawning�a feast for filter feeders. No one yet knows where they mate or give birth.
Sarmin Tangadji, the Papua police officer who escorted the photographic team to where the sharks congregate, was so excited to see them up close that he jumped in. Credit: �Michael Aw/National Geographic. |
Whale sharks also gather off Papua, where artisanal fishermen�hoping to keep their nets and catches intact�offer the whale sharks food.
From the National Geographic article Sharing With Sharks:
Whale sharks are ordinarily loners. But not in one corner of Indonesia. The photographs on these pages, shot some eight miles off the province of Papua, reveal a group of sharks that call on fishermen each day, zipping by one another, looking for handouts near the surface, and nosing the nets�a rare instance when the generally docile fish act, well, like the rest of the sharks.
You can see all the images and read the photo essay here.
Jumat, 16 September 2011
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